Parijat, you must have accidentally turned Bounding Box off.
Check if it's on for you: View > Show Bounding Box (Ctrl+Shift+B)

The selection tool is not showing its feature to select and resize the object or rotate the object. It's just simply moving the selected object and not increasing or decreasing the size.
Kindly help.

You must have accidentally disabled bounding box (Ctrl+Shift+B, View > Show bounding box)

When using the selection tool, I can't change the size of an object anymore.

Having this issue too where sporadically objects will not scale (via normal method of using DS tool to grab corner of bounding box). The boxes are visible at the corners, but when I try to scale the image is grabbed and dragged from that point.
This is affecting my images, text boxes, and vectors.
Highly frustrating. @Illustrator please assist with fix

This happened to me for the first time today, Cmd+shift+B worked for me

I am having this problem as well

Check if you accidentally disabled bounding box (Ctrl+Shift+B)

+1 for Effigy's statement!

Anish, looking at the original post date of Sept 2017, do you not think that 1 year and 7 months to recognise and respond is on the ridiculous side? I'm pretty sure that you have had at least one upgrade in that time, most likely more. Yes, it would appear that the issue is resolved, but it was so long ago that I suspect the anyone who had an issue has long forgotten they even posted here. I'm not sure how Adobe can think that this is an acceptable length of time to respond.

Selection tool does not work properly. It selects the total anchor points of an object, however it does not behave as the Direct Selection Tool, it only allows to move the object. It does not allow to resize. a single or multiple objects selected.

Illustrator version: 23.0.3
OS: Mac OS Mojave 10.14.4

The selection tool will select and move objects, but I cannot grab the corner and resize them. I have to use the direct selection tool and select any anchor points I want to move, even to do a simple re-size

Show bounding box is ON, having the same issue. Can go to object>scale to resize but there are no white squares to pull on to resize the regular way, or to rotate, or do anything else. the selection tool is white in the middle and when you point to a corner it says "path" and if you pull it moves the image...

You can try it:-
View/Show Bounding Box.
Or
Ctrl+Shift+B

Agree. When I bring in images I can't resize them with selection tool... have to use actual pixel size. When I restart app - still doesn't work. When I restart computer - then it resets... sometimes. iMac - updated to Mojave. Illustrator CC 2019

1. Version 23.0.1
2. I was working as usual but suddenly kept closing and running slowly. I had lost what I was doing once. Then opened up again and couldn't extend lines anymore, there wasn't centre handles nor white anchors in any object I draw.

Yes!! Why can't I scale with the direct selection tool anymore?? Why??

This happens to me too.

When I click on any object, text, or image and try to resize it just by clicking and dragging the anchor points, it doesn't resize anymore like it used to. It just moves the object. This is on a Mac in Illustrator CC 2019 23.0.1

Am having the same issue. Any response with answers on this?